Method of connecting tubes in series



Jan. 7, 1936.

J. ROBERTSON ET AL METHOD OF CONNECTING TUBES IN SERIES Original Filed April 16, 1954 INVENTORS 6 P Patented Jan. 7, 1936 UNITED STATES PATENT OFFIQE METHOD OF CONNECTING TUBES 1 SERIES James Robertson and George H. Purdy, San Francisco, Calif.

2 Claims.

Other objects more or less apparent will present themselves or will be speciflcallypointed out in the description of our invention which is to follow.

In the accompanying drawing we have shown a liquid cooler embodying a construction which has been made in accordance with our invention, and in said drawing:

Fig. 1 is a side elevation of a part of the cooler;

Fig. 2 is a vertical section taken on the line 2- -2 of Fig. 1;

Fig. 3 is a section taken on the line 3-3 of Fig. 1; and

Fig. 4 is an enlarged side view, partly in section, of a portion of the cooler showing the manner in which the tubes are mounted in a header and secured together.

Referring to the drawing the numerals I and 2 represent a pair of upright channel type headers having a, plurality of tubes 3 secured thereto and to one another as by solder and interlocking means, and arranged in series and in vertical alignment. Mounted on the headers I and 2 above the topmost of the tubes- 3 is a trough 4 into which quantities of milk or other liquid to be cooled is poured, and below the lowermost tube 3 is mounted a drip pan 5 adapted to receive the liquid passing downwardly over the tubes. trough at its bottom side is provided with aplurality of holes through which the liquid may pass; and the drip panis provided with. an outlet 6 through which the liquid may be discharged into a suitable receptacle. The header 2 is provided at its lower end with a fluid inlet I through which a suitable refrigerant fluid may enter the cooler, and at its upper end with an outlet 8.

Except for the topmost of the tubes 3 which is preferably circular in cross section, the walls of each of the other tubes, at their upper sides, extend'outwardly and. upwardly as at 9 and I0 to provide a hollow lip which furnishes an additional space within the tube for the passage of a refrigerant fluid. The parts 9 and. II) are formed integrally with a slightly curved part II which entirely-encloses the inside of the tube.

The curved part I l of each of those tubes which has the same thereon is secured as by solder to the lower side of the particular tube located above it. The solder attaching the part II to the curved lower side of another tube is evenly distributed along the length of the tubes so as to completely 'close any cracks, thereby preventing the possible accumulation of bacteria. The arrangement of the tubes with the part I I of one tube secured to the underneath side of an adjacent tube provides an improved closed type cooler which may be easily cleaned with a brush or other suitable implement. 1 In order to permit the cooling fluid entering the cooler from the inlet 1 to flow upwardly through the tubes 3 to the outlet 8, we have formed suitable channels at the ends of the tubes so that the fluid may freely pass from one tube into another. The end of the lower tube 3 opposite the inlet I, is joined to the next higher tube by bending and interlocking the walls of the two tubes by means of a suitable tool or die which is forced inwardly against the metals after the 2 part II of the lower tube and the wall of the next higher tube are slit through. The die or tool is so shaped that the walls at the ends of the two tubes are bent outwardly as at I2, thereby providing a channel through'which the liquid 30 may freely pass from the lower tube into the next higher tube. When the ends of the tubes are bent outwardly by the inward pressure applied by the tool or die, the parts 9, I0, and II of the lower tube and the adjacent wall of the next 35 higher tube are flattened out and pressed in overlapping positions against each other. In order that the refrigerant fluid may proceed upwardly through the cooler to the outlet 8, the tubes are arranged in series with channels of the type de- 4 scribed provided at alternate ends thereof. Thus in the same manner that the lower tube and the next higher tube are joined together and provided with a channel at adjacent ends thereof, so is the opposite end of the said next higher tube and 4 the adjacent end of the succeeding higher tube formed with outwardly bent and overlapping sides as at I2 to provide a channel for the passage of the fluid into the said succeeding higher tube.

Thus the adjacent ends of the other tubes are 50 ably cut evenly along vertical planes so they closely fit against the vertical end walls of the headers. The space between the headers and the tubes, as well as the joints where the walls of the tubes are bent outwardly to provide the channels, are filled with solder, as at l3. The overlapping side walls of the tubes where the channels are formed, and the position of the tubes against the end walls of the headers with filled in solder closing all points where leakage of the refrigerant fluid could occur, provides a construction which is exceptionally durable and rigid.

The liquid placed in the trough 4 passes through the holes provided in the bottom of the latter, and drops onto the uppermost of the tubes 3, after which it flows downwardly over the tubes and their parts 9 and I into the drip pan 5. A cooler constructed with the tubes having the outwardly disposed parallel parts 9 and M thereon, provides a greater amount of eficient cooling surface over which the liquid to be cooled passes.

Not only does such a construction present a more eflicient cooler; but the interlocking walls at the ends of the tubes with their shapes being rectangular or semi-rectangular and in close engagement with one another and the Walls of the headers, is capable of withstanding a far greater amount of pressure from the refrigerant fluid passing through it than similar types of devices now in use.

It is to be understood that our invention is susceptible of numerous changes with respect to form, shape and minor details of construction. It therefore is to be understood that the appended claims shall determine the limits our invention may assume rather than the exact disclosures herein made.

In our co-pending application entitled Liquid coolers, filed April 16, 1934, Serial No. 720,823,

issued as Patent No. 2,001,923 on May 21, 1935, of which the present application is a division, we have shown and described a construction made in accordance with our novel method.

We claim: 10

1. In the method of connecting tubes in series, the steps which comprise slitting the adjacent side walls of a pair of substantially parallel tubes from a point at adjacent ends thereof to points toward their central portions, bending the side Walls of the tubes outwardly at their slit ends so that portions of the tubes at points adjacent the slits therein overlap and are in engagement, and then forming the slit ends of the tubes into a substantially rectangular shape.

2. The method of connecting in series a tube having a hollow lip on its side wall with another tube of either the same or difierent construction, which comprises arranging the tubes in parallel relation and placing in contact and securing the hollow lip of one tube to the side wall of the other tube, slitting the end of the hollow lip and the contacting side wall of the tubes for a suitable distance from their adjacent ends, pressing the slit portion of the lip and the slit portion of the side wall outwardly and into firm and overlapping engagement with one another.

JAMES ROBERTSON. GEO. H. PURDY. 

